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Biomedical subjects

H R Morris

Publications and source records attributed to H R Morris.

At least 253 records · Page 14Linked to original sources
PubMed1980

Slow reacting substance of anaphylaxis, SRS-A; assignment of the stereochemistry.

We have recently described the structure elucidation of slow reacting substance of anaphylaxis S(SRS-A) from lung and of a slow reacting substance (SRS) from basophilic leukaemia cells as 5-hydroxy-6-cysteinylglycinyl-7,9,11,14-eicosatetraenoic acid. The stereochemistry of this molecule has now been shown to be 5(S)-hydroxy- 6(R)-cysteinylghlycinyl-7,9-trans-11,14-ciseicosatetraenoic acid by comparison of the synthetic and natural products and their derivatives using mass spectrometric and HPLC chromatographic techniques. The synthetic and natural compounds are also indistinguishable by their pharmacological properties, their conversion by soybean lipoxygenase, and their UV spectra.

Animals↗
PubMed1980

The role of arachidonate lipoxygenase in the release of SRS-A from guinea-pig chopped lung.

The immunological release of SRS-A was investigated in guinea-pig chopped lung. A number of unsaturated fatty acids, all of which are substrates for arachidonate lipoxygenase were found to potentiate the release of SRS-A. This potentiation was enhanced by indomethacin, a cyclo-oxygenase inhibitor, and completely reversed by nordihydroguaiaretic acid (NDGA) and eicosatetraynoic acid (ETA) which inhibit lipoxygenase. This suggests that some aspect of arachidonate lipoxygenase action stimulates release of SRS-A and that release of SRS-A is increased by redirection of arachidonic acid (AA) metabolism via the lipoxygenase pathway (Hamberg, 1976). However, although exogenous 14C-AA increased SRS-A output it was not incorporated into SRS-A.

Animals↗
PubMed1979

Slow-reacting substance of anaphylaxis: studies on purification and characterisation.

We have demonstrated the role of arachidonic acid and lipoxygenase in the genesis of SRS-A and the possible role of lipoxygenases in its metabolism. SRS-A has been purified in microgram quantities together with closely related material. We have identified 5,12 di-hydroxy-6, 8, 10, 14 eicosatetranenoic acid released by antigen challenge, and which we feel is related to SRS-A. Further structural work is in progress.

Animals↗
PubMed1979

Comparative studies on immunologically and non-immunologically produced slow-reacting substances from man, guinea-pig and rat.

1 Slow-reacting substance of anaphylaxis (SRS-A) was produced by antigen challenge of passively sensitized human lung and actively sensitized guinea-pig lung. 2 A slow-reacting substance (SRS) was prepared from the peritoneal fluid of rats treated with calcium ionophore A23187. 3 These substances were extensively purified by charcoal adsorption, Sephadex G-15 gel filtration, ether extraction and reverse phase high pressure liquid chromatography. 4 The three substances are pharmacologically, chemically and chromatographically indistinguishable. 5 Our data suggest that the same SRS entities are released from a variety of tissues and that these acidic lipids may have a wider physiological significance than just anaphylaxis.

Animals↗
PubMed1978

The N-terminal sequences of blood coagulation factor X1 and X2 light chains. Mass-spectrometric identification of twelve residues of gamma-carboxyglutamic acid in their vitamin K-dependent domains.

Peptides (residues 1-42) (bovine prothrombin numbering) from bovine Factor X1 and X2 have been separately purified and digested before mass-spectrometric sequence assignment and identification of gamma-carboxyglutamic acid. N-terminal sequence was found to be identical, and 12 residues of gamma-carboxyglutamic acid were unambiguously identified. The new data give conclusive evidence for the N-terminal primary structure of bovine Factor X and extend present knowledge to show (i) unambiguous assignment of gamma-carboxyglutamic acid residues, including a previously unreported residue of gamma-carboxyglutamic acid at position 40 in both Factor X1 and X2, (ii) the physical difference between Factors X1 and X2 is not due to either different amino acid sequences or different gamma-carboxyglutamic acid contents of the N-terminal 42 residues.

1-Carboxyglutamic Acid↗
PubMed1978

The release of prostaglandins and thromboxanes from guinea-pig lung by slow reacting substance of anaphylaxis, and its inhibition.

1 Rabbit aorta contracting substance (RCS; consisting mainly of thromboxane A2) and prostaglandin-like material were released from guinea-pig isolated perfused lungs by injection of slow reacting substance of anaphylaxis (SRS-A). 2 SRS-A was resistant to boiling and proteolytic enzymes and was therefore distinguished from rabbit aorta contracting substance releasing factor (RCS-RF). 3 The release of RCS and prostaglandin-like material by SRS-A was anatagonized by indomethacin (1 microgram/ml), betamethasone and dexamethasone (4 to 50 microgram/ml). 4 Imidazole (200 microgram/ml) inhibited the formation of thromboxane A2 but not that of prostaglandins. 5 The activity of SRS-A on guinea-pig ileum and its ability to release RCS and prostaglandins were destroyed by incubation with arylsulphatase (0.83 microgram to 1 mg/ml) and with lipoxidase (16.5 to 50 microgram/ml): SRS-A lost activity on incubation with bovine serum albumin (9 microgram/ml) due to protein binding.

Animals↗
PubMed1976

Structure of locust adipokinetic hormone, a neurohormone that regulates lipid utilisation during flight.

Adipokinetic hormone, isolated from locust corpora cardiaca, has been identified as a blocked peptide: PCA-Leu-Asn-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2. The detailed structure is based on mass spectrometric data, substantiated in part by dansyl-Edman and carboxypeptidase data on thermolytic fragments. This is the first peptide hormone from an insect neuroendocrine organ to be fully characterised.

Amino Acid Sequence↗
PubMed1976

Mass-spectrometric identification and sequence location of the ten residues of the new amino acid (gamma-Carboxyglutamic acid) in the N-terminal region of prothrombin.

The detailed mass-spectrometric evidence for our original findings [Magnusson et al. (1974) FEBS Lett. 44, 189-193] of ten gamma-carboxyglutamic acid residues in the N-terminal calcium-binding polypeptide of prothrombin is presented. The identification and sequence location of gamma-carboxyglutamic acid was made by electron-impact and field-desorption studies on acetyl permethyl peptide derivatives, and on the free amino acid. Details of the derivatives formed, and how this new amino acid may be easily recognized and sequenced from the mass spectrum, are given as a basis for future work.

Amino Acid Sequence↗